There are many types of machines which are powered by water-cooled engines operating in environments which present problems with respect to maintaining the air passages through the radiators for the cooling system clear of accumulations of debris. Earth moving machinery operating in dry, dusty atmospheres are faced with such a problem but, more particularly, harvesting equipment such as combines and forage harvesters which operate on crops especially are subjected to the clogging of the radiator air passages with chaff, leaves and other types of debris. Such accumulations of debris greatly minimize the efficiency of the cooling system. In certain climates and situations, insects such as locusts present a substantial problem relative to clogging the air passages of radiators of harvesting equipment, especially in view of the suction fans usually associated with such radiators to draw the ambient air through the air passages to cool the water or other cooling liquids in the cooling system for the engines.
Various attempts have been made in the past to minimize the foregoing difficulties, including the mounting of screens of different kinds over the air passages of radiators for the motors of the machines but, while this somewhat minimizes the entry of accumulating debris in the air passages of a radiator, it nevertheless presents the problem of cleaning the screens and in many circumstances, it is necessary to stop the machine and have an operator physically clean the screen of the accumulated debris. This interferes with the harvesting operation for obvious reasons and has resulted in the development of various devices to clean the screens associated with the radiators of liquid-cooled engines or motors, typical examples of which as follows.
U.S. Pat. No. 2,661,810 to Heth, dated Dec. 8, 1953, comprises a device attached to the inlet of an air conduit leading to a carburetor of a combustion engine for farm implements and includes a transverse screen on the upper end of a vertical air inlet pipe and the incoming air operates the veins on a rotary cleaning member which rotates to dislodge accumulated debris in the pores of the screen.
U.S. Pat. No. 3,475,883 to Sullivan, dated Nov. 4, 1969, pertains to a screen for the inlet to the radiator of an agricultural combine to prevent the inlet of dust and debris to the pores of the radiator and includes a pivoted pendulum-like baffle suspended by gravity from a central axis and adapted to form with respect to a surrounding rotating screen a so-called dead space where the suction of a fan is inapplicable to draw air through the screen and the theory of operation is that the baffle will form an area where dust and debris accumulated on the exterior of the lower portion of the path of travel of the rotary screen will permit at least some of the debris to fall by gravity therefrom and thus tend to keep the screen reasonably clean. Certain kinds of brush-type seals are also associated between the rim of the screen and the supporting frame therefor which is stationary.
U.S. Pat. No. 4,153,436 to Cozine et al, discloses a device similar to that of Sullivan and primarily differs therefrom by drive means which comprise an improvement over the drive means shown in the Sullivan patent.
U.S. Pat. No. 4,233,040 to Vogelaar et al, dated Nov. 11, 1980, pertains to a screen filter for a combine for purposes of keeping the cooling air inlet to an engine relatively free of accumulated debris by utilizing a rotating disc-like screen mounted over the air inlet and utilizing a duct which extends across the face of the disc-like screen from its center to the periphery and changes the direction of air and terminates with an open end adjacent the inlet side of the fan and thereby bypasses the radiator.
The present invention is directed to a very simple but highly effective means for cleaning a screen such as the type of screen associated with the inlet face of a water cooling radiator.